Changes between Version 109 and Version 110 of Scientific Advisory Board/Agenda/2013-06-18


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Timestamp:
2013-07-15T19:52:16+02:00 (7 years ago)
Author:
clevy
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  • Scientific Advisory Board/Agenda/2013-06-18

    v109 v110  
    3333'''Session 3: Sea-ice and biogeochemical components (Leaders: O. Aumont & M. Vancoppenolle)''' 
    3434 
    35 Coming soon... 
     35Biogeocemistry Coming soon... 
     36 
     37__Sea Ice__[[BR]][[BR]]The sea ice session was coupled to biogeochemistry and was very short.[[BR]][[BR]]NEMO is coupled to LIM2-3, to CICE and to GELATO.[[BR]][[BR]]Going towards more generic and flexible interfaces is an objective. In practise, however, an interface always has some strong model dependencies, and full generality can hardly be achieved.[[BR]][[BR]]The developments for sea ice in NEMO were detailed for LIM and include: hpc optimization, ice dynamics, advection of multiple tracers, and the introduction of various complexity levels in the model.[[BR]][[BR]]HPC optimization should be addressed, in particular the fact that the sea ice model is called on all points of the domain.[[BR]][[BR]]The need for a sea ice model in NEMO was still seen as necessary as the interface has to be tested by someone. 
    3638 
    3739'''Session 4: Is AGRIF a major feature of NEMO? (Leaders: L. Debreu & D. Iovino)''' 
     
    7072'''Session 5: Contours and limits of the assimilation component of NEMO''' '''(Leaders: P. Brasseur & S. Dobricic)''' 
    7173 
    72               
    73  
    7474The general concept of an assimilation component within NEMO has been promoted since 2009 with the objective of making assimilation tools for NEMO more readily available to the user community. Based on the consensus that a comprehensive assimilation system cannot be incorporated and maintained in the long term within the NEMO system, the purpose of session 5 was to clarify what should be the contours and limits of the NEMO assimilation component. 4 main questions were addressed and discussed during the meeting: 
    7575 
    76  1.  Is the current partition between built-in, interface and external components of assimilation a reasonable trade-off, or should we move the boundary?  It was agreed that the 3 existing building blocks (OBS, ASM, TAM) should be maintained and further developed in such a way to increase their usefulness by assimilation groups, but also by modeling groups (e.g. using TAM for sensitivity studies).   
    77  1.  While TAM and ASM modules have no equivalent alternatives in the community, the OBS component is an issue since some groups are developing alternative tools to interface NEMO simulations with observational data sets (for assimilation or diagnostic purposes). In the future, one should ensure that the OBS component evolves in such a way that it could be used more systematically by more groups, using more diverse observational data sets.  
    78  1.  Should we have a generic interface for data assimilation schemes based on a modular approach with structures (without writing to the disk) ?  There was no clear-cut position reached on this question, but we believe that this approach should be encouraged in the long term, and further discussed with the assimilation user community (which was not widely represented in the audience).  
    79  1.   In the future, should NEMO include a capability to produce probabilistic information (i.e. ensemble model trajectories), in addition to deterministic runs ? This was recognized as an important goal to be considered in the future, especially by NEMO members concerned with assimilation issues. However, there are several key applications that would benefit from such a capability, which extend beyond the strict scope of ensemble assimilation (e.g. for non-linear modelling sensitivity studies in complement to the linearized TAM approach, uncertainty estimation for climate projections, studies of intrinsic variability and chaotic properties of the ocean, stochastic modelling of model errors etc.). It would be great if this capability would enable on-line computation of ensemble means and spread, as well as various ensemble statistics with observational data. This topic will require further brainstorming in order to define an appropriate roadmap for including this option in future NEMO systems.   
     76 1. Is the current partition between built-in, interface and external components of assimilation a reasonable trade-off, or should we move the boundary?  It was agreed that the 3 existing building blocks (OBS, ASM, TAM) should be maintained and further developed in such a way to increase their usefulness by assimilation groups, but also by modeling groups (e.g. using TAM for sensitivity studies). 
     77 1. While TAM and ASM modules have no equivalent alternatives in the community, the OBS component is an issue since some groups are developing alternative tools to interface NEMO simulations with observational data sets (for assimilation or diagnostic purposes). In the future, one should ensure that the OBS component evolves in such a way that it could be used more systematically by more groups, using more diverse observational data sets. 
     78 1. Should we have a generic interface for data assimilation schemes based on a modular approach with structures (without writing to the disk) ?  There was no clear-cut position reached on this question, but we believe that this approach should be encouraged in the long term, and further discussed with the assimilation user community (which was not widely represented in the audience). 
     79 1. In the future, should NEMO include a capability to produce probabilistic information (i.e. ensemble model trajectories), in addition to deterministic runs ? This was recognized as an important goal to be considered in the future, especially by NEMO members concerned with assimilation issues. However, there are several key applications that would benefit from such a capability, which extend beyond the strict scope of ensemble assimilation (e.g. for non-linear modelling sensitivity studies in complement to the linearized TAM approach, uncertainty estimation for climate projections, studies of intrinsic variability and chaotic properties of the ocean, stochastic modelling of model errors etc.). It would be great if this capability would enable on-line computation of ensemble means and spread, as well as various ensemble statistics with observational data. This topic will require further brainstorming in order to define an appropriate roadmap for including this option in future NEMO systems. 
    8080 
    8181'''Session 6: NEMO validation and contours of user support  (Leaders : A. Guarnieri & J. Siddorn)'''